*{
    margin: 0;
    padding: 0;
}
body,html{
    width: 100%;
    height: 100%;
}
.box{
    height: 100%;
    width: 100%; 
}
.banner{
    display: block;
}
.banner:nth-of-type(1){
    margin-bottom: 0.05rem;
}
.banner img{
    display: block;
    width: 100%;
}